I do agree that the usual conventions would apply also to any colonial possession Venice might acquire: in the New World names of islands would most likely be name of saints most venerated by the inhabitants of Venice, the more so if the discovery or acquisition of apn island coincides or at least is close to the saint's feast day (San Marco, San Nicola, Madonna della salute and soo one: just choose from a list of Venice churches). Forts might be named after ruling doges, or successful commanders. Town or cities would most likely be named after a township in Veneto or a sestiere of Venice or an island in the lagoon. I'd assume that if settlers are coming mainly from a particular area of the Stato de Tera or the Stato de Mar the name of the settlement would reflect it (e.g. Nova Treviso or Nova Pola).
In the Far East I'd say that local names would be kept, almost certainly transliterated in a way which suit Venetial language.
Mind, it would be difficult for Venice to acquire islands in the Caribbean Sea or in the Far East. Acquiring large swathes of land suitable for a true settler colony would be even harder barring really momentous changes in the history of the Serenissima. If Venice proves to be capable or lucky enough, I'd bet that the names of these settlement colonies might strangely prove similar to OTL ones in many cases (Argentina, Brasil or Australia, for example). The difference would be that New South Wales would possibly be named Novo Veneto or Nova Dalmazia.